Process for treating human nails and hair with dimethylol thiourea compositions



Get. 24, 1967 Y B.JOOS 3,349,000

PROCESS FOR TREATING HUMAN NAILS AND HAIR WITH DIMETHYLOL THIOUREACOMPOSITIONS Filed Jan. 21, 1964 LOAD A 1 I F] 1 l EL 0A/fiAT/0/V Fig- 2EONHAT/ON Faterated Got. 24-, 1967 3,349,000 PROCESS FDR TREATING HUMANNAILS AND HAIR WITH DEMETHYLOL THIOUA COMPO- SITIONS Bernhard lines, 23Kurfirstenstrasse,

Zurich, Switzerland Filed Jan. 21, 1964, Ser. No. 339,271

Claims priority, application Switzerland, Jan. 24, 1963, 855/ 63 3Claims. (Cl. 167S5) The present invention relates to a cosmetic processwherein solid keratinous material such as hair and nails are .givenimproved strength and elasticity. More particularly, the presentinvention relates to a process for improving strength and elasticity ofsaid material by treating it with a solution or suspension of reactionproducts of thiourea and aldehyde. When applied to human fingernails ortoenails, the process of the present invention improves resistance ofthe nails to cracking, splitting, laminating or similar damage. Humanhair treated by the process of the present invention ha improvedelasticity and is better dressable. By the present process the loss oforiginal properties of the hair, especially those related to theelasticity, which were damaged by preceding treatments such asbleaching, permanent wave, dyeing or the like is partially compensated;further naturally weak hair may be strengthened by said process. Theprocess of the present invention further makes use of compositions whichare absolutely free of substances which may produce undesirable sideeffects.

It is already known that strength and elasticity of keratinous materialsmay be increased by treatment with aldehydes. The use of aldehydes inthe cosmetic field however suffers from the disadvantage that besidesthe aforementioned effects the aldehydes produce undesirablesideeffects, such as inflammation, hardening and/ or formation of hornon adjacent skin areas. Apart from this, the free aldehydes prove tohave a rather dangerous toxic effect, especially on the nerve cells ofthe skin and the capillaries.

The present invention is based on the discovery that products obtainedfrom the reaction of formaldehyde with thiourea impart to nativekeratins higher elasticity and strength than do the free aldehydes andmoreover do not produce any undesirable side effects. In other words,the invention is based on a process of strengthening keratinousmaterial, especially nails and hair, wherein the keratinous material istreated with a dilute organic or aqueous dispersion or solution ofdimethylol thiourea. The principal effect of the dimethylol thioureaapplied to the keratinous material apparently is to modify the surface(a) by reaction with free amino groups of the keratinous material, and(b) by polymerization of the dimethylol thiourea layer so produced onthe keratin. As is known, aldehydes impart to keratins strength andimproved elasticity which properties obviously result from reaction ofthe aldehydes with amino groups of the keratins. When e.g. formaldehydeis used methylene bridges are formed. In the same manner with dimethylolthiourea methylene bridges between one methylol group of said substancesand the amino groups of the keratins are built.

Furthermore, the aforementioned products are capable of polymerizing.After reaction with the keratins polymerization occurs and thereby afilm is formed which is tightly anchored to the keratins, the filmimparting to the nails, hair, fibres or furs coated therewith usefulnovel properties both from the mechanical as well as chemical point ofview. The film effects an increase in elasticity, plasticity and tensilestrength; it is practically insoluble in water and various organicsolvents, which is of utmost importance for the purpose it is to serve.The polymerization and the film formation, occurring upon theapplication can be supported by adding polymerization catalysts that arecompatible with the skin. Weak acids and salts, such as phosphoric acid,lactic acid, acetic acid, ammonium chloride, aluminum chloride areparticularly suitable for the purpose.

The process according to the present invention is preferably carried outby using aqueous solutions. Its effectiveness can be objectively proved,e.g. by testing single hairs for their elasticity.

Dimethylolthiourea as used for the process according to the invention isin general prepared from thiourea and formaldehyde; the preparation mayproceed e.g. in the following manner:

Thiourea is dissolved in water and formaldehyde is added in the form ofan aqueous 40% solution. While continuously stirring the solutionconcentrated (20%) soda lye is added until the pH value reaches 8.5.After cooling in the refrigerator for several days crystals ofdimethylol-thiourea precipitate from the solution; they are filtered bymeans of suction, washed with an aqueous thiourea solution, and dried.Dimethylolurea in cold water yields solutions of about 15%Concentration.

The final composition used for the process of the invention may beobtained as follows:

In a first container 5 to 15 parts by weight of dimethylolurea ordimethylolthiourea are dissolved in 80 parts by volume of warm water at50 to 60 C. In another container 1 to 10 parts by weight of primarysodium phosphate or 0.2 to 2 parts by weight of an organic acidcompatible with the skin, especially of an organic acid normally presentin living organisms, such as e.g. lactic acid, citric acid,glycerophosphoric acid, or the like, are dissolved in 20 parts by volumeof water. (Here as in the subsequent examples parts by weight arerelated to parts by volume a grams to milliliters.) While stirring thesecond solution is added to the first one so that a clear, transparentsolution develops, the pH value of which is adjusted, if need be, to 2-6with diluted soda lye. The compositions for carrying out the process ofthe invention generally contain about 1 to 15% by weight, preferably 5to 15% by weight of thiourea. The acid content may be about 0.2 to 2% byweight, while bases, salts and buffer substances are added in theproportions necessary to obtain the desired pH value. The solution thusobtained may be used for the treatment of nails.

A similar solution may be employed for hair; preferably it contains athickener, e.g., 1-5 percent by weight of polyvinylpyrrolidone and/ or0.2-2 percent by weight of polyethyleneglycol, or other thickeners knownper se.

In either solution the water can be replaced partly or wholly by organicsolvents, such as, e.g., ethyl alcohol, dioxane, dioxolane, or mixturesthereof. The solutions or dispersions of the invention contain no freealdehydes.

Instead of treatment with acidic solutions the process of the inventionmay be practiced by first applying a weak acid to the keratinoussubstrate and then wetting with a neutral or even slightly basicsolution of dimethylol thiourea. Further it is possible to start theprocess with wetting the surface of the keratinous material with theneutral or slightly basic solution of dimethylol thiourea and thenapplying the weak acid to the so-treated surface.

In treating hair or nails with such solutions the following effects areobtained:

Solutions of dimethylol thiourea, such as specified in the followingexamples, react with the keratinous substances of the nails or -hair sothat new combinations of dimethylol thiourea with keratin develop. Thecompounds thus obtained are in particular capable of polymerizing withone another producing at the same time film-forming polymers that areinsoluble in water.

The nature of the chemical process involved can be investigated by colorreactions; with keratin treated according to the invention the Ninhydrintest is negative. Nails or hair treated in the manner of the inventiongive no color with Ninhydrin thus indicating that free keratin and freeamino groups are no longer present.

The treated and thus modified keratins display an increased elasticity,plasticity and resistance to breaking without losing any of their usualdesirable properties. Such improvement can be specifically tested bysubjecting untreated hair as well as hair that has been treated by theprocess according to this invention to a recordable stressgit will beseen after the treatment of the hair by the method herein described thatelasticity, plasticity and resistance to breaking have been increased.Results of corresponding tests are given in the annexed diagrams.

Merhod.A hair is placed between two clamps and loaded by continuouslyincreasing weights whereby the exerted stress however remains beyond thevalue leading to break (Sadamel Microtester, Type Mi 44, No. C 620,-634). Then the hair reversely is unloaded in the same way. Theelongation in case of increasing and decreasing load is recordeddiagrammatically. From the area included by the two curves (increasingand decreasing load versus elongation) and the inclination of the curvesdifferences in elasticity and strength of the hair may be taken.

Test No. 1.A normal untreated hair of a woman was cut into identicalpieces of 3 cm. length each. The diameters of the individual test pieceswere compared and samples of identical diameter were used for the test.One untreated piece was tested in the above manner and curve 1 of FIG. 1was obtained.

A second sample was immersed in a 10% aqueous solution of dimethylolthiourea (pH value 5) for minutes and dried at a temperature of 30 to 40C. for to minutes. Thereafter this sample was subjected to the same testas the untreated hair; the result is given by curve 2 of FIG. 1.

Test N0. 2.--As described in Test No. 1 the properties of an untreatedsample of hair were investigated and recorded (FIG. 2, curve 1) A secondsample was immersed into a 8% solution of dimethylol thiourea in aqueousethanol (pH=5) for 10 minutes. After drying the hair was tested andcurve 2 of FIG. 2 was obtained.

From comparison of the curves obtained with treated and untreated hairit is evidentthat the treatment with dimethylolthiourea yields asignificant improvement of strength and elasticity of the hair.

Repeated treatment of fingernails or toenailswith the solutions asspecified will result in a strengthening of the nails which,nevertheless, retain their natural. elasticity, and any previoustendency of the nails to crack will be eliminated or at least decreased.

The presentinvention will be further illustrated by the followingexamples. In these examples parts by weight are related to parts byvolume like grams to milliliters.

Example 1 A solution prepared from 2 parts by weight of dimethylolthiourea, 0.2 part by weight of glycerophosphoric acid, 20 parts byweight of33% ethanol and 0.7 part by volume of 1 N aqueous NaOH andhaving a pH value of 5 is applied to finger nails that are free from anynail polish.

A it The solution dries within a few minutes, whereupon the nails ifdesired may be enamelled. The nails so treated exhibit improvedresistance to cracking and splitting.

Example 2 A solution producing the same etfects like that of Example 1is prepared from the 2 parts by weight of dimethylol urea, 0.2 part byweight of glycerophosphoric acid, 6.5 parts by weight of ethyl alcohol(96%), 13.5 parts by weight of dioxolane and 0.7 part by volume of 1 Naqueous NaOH. It is applied to finger or toe nails in the same manner asdescribed in Example 1.

Example 3 A composition of matter to be used as nail hardeningcomposition is obtained as follows:

2 parts by weight of dimethylol thiourea, 0.2 part by weight ofglycerophosphoric acid, 6.5 parts by weight of ethyl alcohol (96%) and13.5 parts by weight of dioxane are mixed and the mixture is adjusted toa pH value of 4 by addition of 1 N aqueous sodium hydroxide to yield aneffective nail strengthening composition.

Example 4 About 20-30 milliliters of a solution prepared from 15 partsby weight of dimethylol thiourea, 150 parts by weight of aqueous ethylalcohol (15% ethanol) and 7.5 parts by weight of glycerophosphoric acid,the total mixture having a pH value of value of 2.7, are applied to thehead of a woman. and rubbed into the hair after. shampooing. Beforeapplication of the aforementioned.

composition the hair had been dried in the best possible way by means ofa towel. Now the hair is set and dried by means of a drying apparatus atthe usual temperature of about 40 C. for 30 to 45 minutes. Thereafterthe hair is dressed as usual. The dressing so obtained can be fairlymaintained. After repeated treatment the hair becomes very elastic andstronger.

Example 5 A composition of matter which may be used as described inExample 4 is obtained from the following constituents: 7.5 parts byweight of dimethylol urea, 150 parts by weight of aqueous, ethyl alcohol(15% ethanol), 7.5 parts by weight of glycerophosphoric acid; The pHvalue of the resulting solution is 2.7.

Example 6 A further treating solution which may be used in the processof the present invention is obtained by mixing about 1 to about 15% byweight of the. total composition.

of dimethylol thiourea, about 0.2 to about 2% by weight of an acidiccompound selected from the group consisting of phosphoric acid, lacticacid, citric acid, acetic acid,

' glycerophosphoric acid and acid salts thereof, and a liquid diluent.

2. A process according to claim 1 wherein the fluid composition containsabout 5 to 15 by weight of the total composition of dimethylol thiourea.

3. A processaccording to claim 1 wherein the liquid diluent is a memberselected from the group consisting of water, alcohols, dioxane,dioxolane and mixtures thereof.

(References on following page) References Cited UNITED STATES PATENTSSchwarzkopf 16787 Brown 16787 5 Maxwell 16785 X Habicht et a1. 16787Cassidy 16787 6 FOREIGN PATENTS 1,015,804 8/1952 France.

ALBERT T. MEYERS, Primary Examiner.

JULIAN S. LEVITT, Examiner.

VERA C. CLARKE, Assistant Examiner.

1. A PROCESS FOR IMPROVING THE STRENGTH AND ELASTICITY OF HUMAN NAILSAND HAIR WHICH COMPRISES WETTING THE SURFACE THEREOF WITH A FLUIDCOMPOSITION CONTAINING FROM ABOUT 1 TO ABOUT 15% BY WEIGHT OF THE TOTALCOMPOSITION OF DIMETHYLOL THIOUREA, ABOUT 0.2 TO ABOUT 2% BY WEIGHT OFAN ACIDIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF PHOSPHORICACID, LACTIC ACID, CITRIC ACID, ACETIC ACID, GLYCEROPHOSPHORIC ACID ANDACID SALTS THEREOF, AND A LIQUID DILUENT.